Keel construction for boats or ships



Jan. 946. A. E LUDERSA 2,391,990

KEEL CONSTRUCTION FOR BOATS OR SHPS Filed June l5, 1944 IN VEN TOR. ,4L hef-o ft l. 110Mo' @alla @Me f' irren/v5 yf Patented Jan. 1, 1.946

.PATENT or Fics CSTitiJigFoR 'B'T'SoR Alfred E. Laders, stamm-dicen@ .Application .mi 1t, 194dsei N65 '546.473

(nieuw s) fet-:rama

' Thisinventionrelates to vaC kee o f a vessel having 'sides' glued to the keel.`""The object ofthe invention is to provide a strong-and durableY keel which may beiirmly secured to the sides without danger'oi disruption of thejoint fromswelling orshrinking of the keel. l Y. n

v`In recent years a system of building boathulls of plywood constructionhasbeen developed;` that is withsuccelssive laminae of wood, the grain extending inv diierent directions, glued together, and it has been found practicable to use Waterproof glue which is now on the market. A diniculty has developed, however, in securing the plywood sides to the keel of vessels requiring a keel.

It has been proposed for example to make the entire keel of glued laminae and glue the laminated sides to it, but such keels do not possess the simplicity and rigidity of the standard solid keel, and are more liable to injury, as well as being more expensive. On the other hand, a solid timber keel has a tendency to swell or shrink in thickness and width, while the diagonally laid planking layers constituting the vessel sides have no compensating change in shape, hence the swelling or shrinking of the keel tends to weaken the glue layers between the keel and sides and may result in breaking the glue in these regions, or breaking the adjacent br'es of the wood, causing leakage.

The present invention seeks to obtain the advantages of both the laminated keel and the solid timber keel without the disadvantages of either.

I accomplish my object by taking a strong, solid beam for the keel and forming ne saw cuts in the opposite edges of the beam. In the process of gluing up, these saw kerfs are lled with adhesive composition, with the result that the edge portion of the keel, after the glue has set, will take on the same characteristics as the glued sides, preventing relative shifting between the side and keel, resulting in a secure and permanent joint.

I have illustrated my invention in the drawing hereof, in which Fig. 1 is a cross section through the hull f a boat built of plywood sides and having my improved solid timber keel; Fig. 2 is a longitudinal vertical fragmentary section of the keel, the plane being indicated by the line 2 2 on Fig. 1; Fig. 3 is a cross section of a portion of the keel and a portion of the side on a much larger scale than the preceding figures, the plane of the section being indicated for instance by the line 3-3 on Fig. 2.

In the drawing, A indicates the keel member of my construction. This is a'solid'ldrigtudinal beam ofv wood. 3 the Yopr'iosite'.`up`-and-dbwn iaces' of the I beam, which are shaped' tobe'en- -gaged` by the sides, I 4make a. number ofnarrow saw cuts a extending vinwardly froidv opposite sidesof the keel beam. These kerfs'extend ingitudinally throughout the length of thebeam'and are substantially equi-distant trom" eachv other and'v are paralll'witli thetop and'lottoml planes of the beam.' These' kerfs become "lled with waterproof glue, as indicated especially in Fig. 3.

The sides of the boat B are comprised of a series of thin laminae glued together by waterproof glue. In Fig. 3, I have shown nine laminae, which I regard as la satisfactory number. The number, however, may be varied as desired, and the showing in Figs. 1 and 2 of several laminae is to be taken as indicating anyconvenient number.

The glue ilm C between the keel and sides, and preferably the glue between the diierent laminae B is of the same character as the glue occupying the kerfs a. The glue layers in the kerfs united to the glue layer between the keel and side forms a rigid connection between the keel and side, which prevents any deleterious action on the junction from the swelling or shrinkage of the keel. The main body of the keel may swell, for instance, as indicated by the broken line a in Fig. 3, or may shrink, while the comparatively thin portions between the saw kerfs are retained at their original dimensions by the water-proof glue which penetrates the pores of the beam p0rtions between the kerfs and prevents such access of moisture as might cause trouble.

It will be seen from the description given that I am able by this invention to obtain the advantages of a solid timber keel Without danger of disruption between it and the plywood sides of the vessel.

The preferred method of forming the vessel hul1 embodying this improved keel is to shape the beam for the keel properly at the top and bottom and side edges and then by sawing action form the kerfs in the opposite edges. Before the sides are applied a quantity of water-proof glue is put on the kei-fed edges and into the kerfs of the beam sides and the rst layer of the siding with its grain extending diagonally of the keel, as shown in Fig. 2, is clamped against the side of the keel. Then glue is applied to the outer face of the i'lrst lamina of the side, the second lamina applied and formed and this method is continued, each lamina having its grain extending crosswise of the preceding lamina, until the side is of the desired divergent directions, the innermost lamina of the two sides being glued to the outer edges of the v solid keel beam, said beam having on each side longitudinal kerfs parallel with each other and extending inwardly from the edge of the beam part-Way toward the center, and water-proof glue occupying the kerfs and forming layers also between the edges of the beam and the adjacent laminae of the sides. I

2.` A keel and planking construction for a vessel comprising a solid beam of wood with its opposite faces formed for engagement by the sides of the hull, the beam at such opposite faces being formed with inwardly directed parallel longitudinal kerfs containingl thin layers of glue and vessel planking having an inner Alayer extending across the kerfed face of the beam and glued thereto.

3. The method of building a. boat keel comprising taking a longitudinal beam, making fine saw cuts in l the edge thereof, thereafter applying water-proof glue to such edge which glue enters the cuts, applying a layer of planking to that edge of the beam and securing it by such glue.

4. The method of building a boat keel comprising taking a solid longitudinal wooden beam, making ne saw cuts longitudinally of the beam in the opposite v edges thereof,l applying waterproof glue tosuch edges` and allowingdt to enter the cuts, gluing thin layers of Wood to such edges of the beam, and successively adding a glue layer and another layer of wood with its grain crossing the preceding layer until each side is composed of several layers of wood with intermediate glue, using the same character of glue for all the junctions. 

